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Modifications of tyrosine and catecholamines by peroxynitrite, nitrite and nitrate
Wu-Nan Kuo1, Joseph M Kocis, Luvina K Guruvadoo
1Division of Science and Mathematics, Bethune-Cookman College, Daytona Beach, Florida 32114, USA. kuow@cookman.edu
Frontiers in Bioscience : a Journal and Virtual Library
|April 18, 2003
Summary
Reactions between catecholamines and nitrite or peroxynitrite produce colored compounds. These reactions, including nitration and nitrosation, alter compound mobility and absorbance, indicating complex chemical transformations.
Area of Science:
- Biochemistry
- Analytical Chemistry
- Organic Chemistry
Background:
- Catecholamines like dopamine and epinephrine are crucial neurotransmitters.
- Nitrite and peroxynitrite are reactive nitrogen species with significant biological implications.
- Understanding their reactions is vital for biochemical and toxicological studies.
Purpose of the Study:
- To investigate the reaction products of L-tyrosine, L-dopa, dopamine, L-norepinephrine, and L-epinephrine with peroxynitrite or nitrite.
- To characterize the physical and chemical properties of these reaction products.
- To elucidate the types of chemical reactions occurring, such as nitration and nitrosation.
Main Methods:
- Incubation of various catecholamines and L-tyrosine with peroxynitrite or nitrite at pH 7.0 in potassium phosphate buffer.
- Analysis of reaction products using silica thin layer chromatography (TLC).
- Spectrophotometric analysis of absorbance changes between 400-540 nm.
Main Results:
- Colored products were generated from the reactions.
- TLC revealed unique colors and mobility patterns for each product.
- Nitrite treatment led to multiple colored spots and longer bands, indicating compound formation.
- Nitrate incubation resulted in significantly increased mobilities of catecholamines.
Conclusions:
- The reactions involve nitration and nitrosation, forming various active intermediates.
- Peroxynitrite and nitrite induce complex chemical modifications in catecholamines.
- These findings highlight the reactivity of catecholamines with reactive nitrogen species.